Ruby: undefined method `<<' for nil:NilClass error message

I’m trying to load some data from a csv file into my program and get the following error message: undefined method `<<‘ for nil:NilClass error message

Here is my code:

def load_students
    file = File.open("students.csv", "r")
    file.readlines.each do | line |
        name, cohort = line.chomp.split(",")
        @students << ({:name => name, :cohort => cohort.to_sym})
    end
    file.close
end 

@students refers to an empty array.

Any idea what the issue is?

Thanks!

>Solution :

@students refers to an empty array.

Does it? (Apparently not, because the error message says it’s nil!!) You never showed us where this variable get initialised.

In ruby, all instance variables evaluate to nil by default, if you don’t define them as something else.